Allodynia

Allodynia is a very uncomfortable heightened sensitivity to touch. Slight touches that normally are not even noticed can cause pain.

In a migraineur, this usually starts after the migraine hits. Most often the pain in on the skin (cutaneous allodynia) - on the scalp and also on the arms. This can make wearing of jewelry, shaving (face), or even the normal sleeves on your clothes unbearable. Every movement causes more pain. Brushing hair, heat from a stove - even wind can become a problem.

Muscle tenderness can also be a symptom. Tenderness of the muscles in your head and neck, increased pain when doing normal movement such as bending or shaking your head. These symptoms can continue to develop hours after your migraine attack begins.

What causes this pain? It is believed that it may result from the neurons in the brain which are activated during migraine and may trigger the worsening hypersensitivity. These same symptoms are being studied in patients with various types of headache not classified as migraine.

Studying this phenomenon is helping researchers understand how changes travel throughout the brain and body during a migraine attack. As we specify which neurotransmitters are involved, it will help us know how to target future headache and migraine treatment. It has been discovered that the common migraine class of drugs, triptans, are much less likely to help once this hypersensitivity has begun. The key in this case is to take them early on in a migraine attack, before the symptoms become too "entrenched". See this issue of HeadWay for more on different triptans and allodynia.

References:The development of cutaneous allodynia during a migraine attack Clinical evidence for the sequential recruitment of spinal and supraspinal nociceptive neurons in migraine by Rami Burstein1, Michael F. Cutrer and David Yarnitsky1, Oxford University Press 2000; Migraine and Other Headaches by Drs William B Young and Stephen D Silberstein; MedicineNet.com article on the topic, reviewed 10 Nov '03